ASME B36.19M (stainless steel pipe) · DN 40
Outside diameter 1.900" (48.26 mm), wall 0.109" (2.77 mm), inside diameter 1.682" (42.72 mm).
| Trade size | NPS 1-1/2 · DN 40 |
|---|---|
| Schedule | Schedule 10S |
| Standard | ASME B36.19M (stainless steel pipe) |
| Outside diameter | 1.900" · 48.26 mm · designated 48.3 mm in the metric column |
| Wall thickness | 0.109" · 2.77 mm |
| Inside diameter | 1.682" · 42.72 mm |
| Weight, plain end | not published |
Nominal Pipe Size is a label, not a measurement. NPS 1-1/2 pipe has an outside diameter of 1.900 inches, and it keeps that outside diameter in every schedule made. What the schedule number changes is the wall: at schedule 10s the wall is 0.109 inches, so the bore comes out at 1.682 inches.
That is the practical consequence. Fittings, flanges, supports and threading dies are sized to the outside diameter, so they fit any schedule of the same trade size. Flow, pressure drop and anything that has to pass through the pipe depend on the inside diameter, which changes with every schedule. Order by trade size and schedule; work your hydraulics from the bore.
Same outside diameter of 1.900 inches throughout - only the wall and the bore move.
| Schedule | Wall (in) | ID (in) | Weight (lb/ft) |
|---|---|---|---|
| Schedule 5 | 0.065 | 1.770 | 1.28 |
| Schedule 10 | 0.109 | 1.682 | 2.09 |
| Schedule 30 | 0.125 | 1.650 | 2.37 |
| Schedule 40 | 0.145 | 1.610 | 2.72 |
| Schedule 80 | 0.200 | 1.500 | 3.63 |
| Schedule 160 | 0.281 | 1.338 | 4.86 |
| Standard wall (STD) | 0.145 | 1.610 | 2.72 |
| Extra strong (XS) | 0.200 | 1.500 | 3.63 |
| Double extra strong (XXS) | 0.400 | 1.100 | 6.41 |
| Schedule 5S | 0.065 | 1.770 | not published |
| Schedule 40S | 0.145 | 1.610 | not published |
| Schedule 80S | 0.200 | 1.500 | not published |
0.109 inches (2.77 mm). The outside diameter is 1.900 inches (48.26 mm) whatever the schedule, so this wall leaves an inside diameter of 1.682 inches.
1.682 inches (42.72 mm). Inside diameter is outside diameter minus twice the wall: 1.900 - 2 x 0.109 = 1.682 inches.
No. NPS 1-1/2 is a trade size, not a measurement. The pipe measures 1.900 inches across the outside and 1.682 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.
This table runs from NPS 1/8 to NPS 24 and stops there. ASME B36.10M itself continues to NPS 80; those larger sizes are not carried here, so a size above NPS 24 is missing rather than undefined.
Dimensions are as defined by ASME B36.19M (stainless steel pipe). This site is an independent reference and is not affiliated with, endorsed by or approved by any standards body.
Every value on this page was cross-checked against 3 independent published sources:
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